#include <bits/stdc++.h>

using namespace std;

int main() {
    //cin读入优化
    std::ios::sync_with_stdio(false);
    //输入+输出重定向
    freopen("../1296.txt", "r", stdin);

    int n;
    cin >> n;
    vector<int> a(n + 1, 0);
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
    }
    int maxx = -1;
    //两层循环，找到每组组合，然后取gcd,打擂台找到最大值
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= n; j++) {
            if (i == j) continue;
            maxx = max(maxx, __gcd(a[i], a[j]));
        }
    }
    cout << maxx << endl;
    //关闭文件
    fclose(stdin);
    return 0;
}